This article reports a study of the discourse of shared lesson planning sessions in the early stages of a pre-service TESOL certificate course. The study focuses on "lesson planning conferences" (LPCs), in which a teacher educator and a group of student teachers worked on one student teacher's lesson plan. It describes the discursive practices through which lesson plans emerged and through which student teachers constructed personal practical knowledge and identity as they negotiated the process of becoming members of the community of practice of English language teachers. The study revealed the LPCs to be a dynamic and recursive process in which problems of instruction emerged and solutions were suggested. While the teacher educators produced more meanings related to personal practical knowledge, the student teachers had a substantial share in the discursive resources with which meanings were exchanged. The analysis also shows how participants engaged with the practice of planning for teaching through such discursive acts as producing directives, proposing actions, evaluating, articulating teaching principles and imagining classroom events.The article argues that --in spite of some limitations--shared lesson planning is a promising strategy for the construction of novice language teachers' personal practical knowledge and professional identities. (Contains 2 tables and 2 figures.)